Non-neoplastic Polyps Flashcards
Describe the epidemiology of non-neoplastic polyps.
- Prevalence >60y: 30-40%
- Men 1.5:1 female RR
- High risk adenoma development associated with >3 polyps at previous colonoscopy
What is FAP?
- Autosomal dominant condition caused by germline APC gene mutations.
- 100-1000s colorectal adenomas
- 100% risk for CRC at 40 w/o colectomy
- May have extra intestinal manifestations
What are the extracolonic features of FAP?
-Duodenal and periampullary neoplasia
-Desmoids
-Congenital hypertrophy of the retinal pigment epithelium (CHRPE)
-Osteomas
-Fibromas
-Epidermoid cysts
(FAP + last 3 = Gardner’s syndrome)
How are adenomatous polyps classified histologically?
Tubular, villous, tubulovillous
Why is important to identify adenomatous polyps?
Premalignant lesion; exposure of its surface to faecal stream may initiate development of adenocarcinoma.
Management of adenomatous polyp finding?
- Colonoscopy: complete examination of large bowel
- Remove all lesions
- Lifelong surveillance
What is Peutz-Jegher’s syndrome?
PJS rare, autosomal dominant disorder with hamartomatous polyposis from mutation in STK11 gene.
Fx: mucocutaneous pigmentation and GIT polyposis. Cancer risk = 90% lifetime.
Describe the pathophysiology of polyp development.
Proliferation in polyp not limited to base of tubules and differentiation of cells absent > dysplasia.
Adenoma ->carcinoma sequence with double hit deactivation of APC genes, accumulation of mutations (p53, K-ras).
What are the classifications of neoplastic polyps?
- Adenomas (most common)
- Polypoid adenocarcinomas
- Lipomas, leiomyomas, lymphomatous polyps
What are the classifications of non-neoplastic polyps?
- Hyperplastic polyps
- Inflammatory polyps (e.g. UC/CD)
- Lymphoid polyps, hamartomas
What are the RFx for polyps?
- increasing age
- FHx
- previous history of polyps